Categories: C-C Bond Formation > Oxygen-containing molecules > α,β-unsaturated compounds >
Synthesis of substituted α,β-unsaturated compounds
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Recent Literature
A highly regioselective vinylogous aldol reaction catalyzed by SiCl4
and a chiral phosphoramide, provides δ-hydroxy enones for a variety of
aldehyde and dienol ether structures in good yields, excellent
enantioselectivities, and in some cases excellent anti
diastereoselectivities.
S. E. Denmark, G. L. Beutner, J. Am. Chem. Soc., 2003,
125, 7800-7801.
N,O-Silyl dienyl ketene acetals are useful reagents for highly
enantioselective vinylogous aldol additions to various aldehydes in the
presence of SiCl4 and the catalytic action of a chiral
phosphoramide.
S. E. Denmark, J. R. Heemstra, Jr., J. Am. Chem. Soc.,
2006,
128, 1038-1039.
The weakly acidic species, silicon tetrachloride (SiCl4), can be
activated by binding of a strongly Lewis basic chiral phosphoramide, leading
to in situ formation of a chiral Lewis acid for catalysis of the aldol
reaction of silyl ketene acetals and silyl dienol ethers (vinylogous aldol
reactions) to conjugated and nonconjugated aldehydes. The high levels of
regio-, anti
diastereo-, and enantioselectivity observed are discussed.
S. E. Denmark, G. L. Beutner, T. Wynn, M. D. Eastgate, J. Am. Chem. Soc.,
2005,
127, 3774-3789.
A nickel-catalyzed cross-coupling of allylic alkyl ethers with organoboron
compounds provides the corresponding products in very good yields via the
cleavage of the inert C(sp3)-O(alkyl) bonds with wide functional
group tolerance and excellent regioselectivity. A gram-scale reaction and
late-stage modification of biologically active compounds further prove the
practicality of this method.
X. Li, Y. Li, Z. Zhang, X. Shi, R. Liu, Z. Wang, X. Li, D. Shi, Org. Lett., 2021, 23,
6612-6616.